提出了合成甲基乙二醛1,2-双-(N,N-二甲基hydr)的方法。首次显示了其以马来酸酐为富电子二烯参与狄尔斯-阿尔德反应的可能性。在湿介质中观察到的这些试剂的第二反应是起始二烯的肼盐与马来酸的形成。通过分子能量的量子化学计算和13 C NMR化学位移的分析揭示了四种可能形式中最可能的质子化二烯结构。
Regioselectivity of the hydrolysis of 2-(1-alkoxyvinyl)-substituted imidazolidines, 1,3-thiazolidines, and 1,3-oxazolidines
摘要:
2-(1-Alkoxyvinyl)-1,3-thiazolidines reacted with H2O or D2O in the presence of 105 mol % of p-toluenesulfonic acid or trifluoroacetic acid (20 degrees C, 1 h) to give 2-acetyl-1,3-thiazolidine in quantitative yield. 2-(1-Alkoxyvinyl)-3,5-diphenylimidazolidines underwent hydrolysis in the presence of 20 mol % of an acid (20 degrees C, 24 h) at the vinyloxy group with high regioselectivity yielding 2-acetylimidazolidines. Hydrolysis of 2-(1-alkoxyvinyl)-3-phenyl-1,3-oxazolidines in the presence of 10 mol % of p-toluenesulfonic acid (20 degrees C, 5 days) takes two pathways, one of which involves the endocyclic C-O bond with ring opening and the other involves the vinyloxy group to produce 2-acetyl-3-phenyl-1,3-oxazolidine. Unlike phenyl-substituted 1,3-thiazolidines and imidazolidines, hydrolysis of their 3-methyl-and 3,5-dimethyl-substituted analogs in acid medium occurs mainly via ring opening. The observed hydrolysis pathways were interpreted in terms of B3PW91/6-311G(d,p) quantum-chemical calculations.
Reaction of 2-Alkoxypropenals with α-Hydroxyamino Oximes and 1,2-Bis(hydroxyamino)cyclohexane
作者:N. A. Keiko、E. A. Funtikova、L. I. Larina、G. I. Sarapulova、D. G. Mazhukin、T. V. Rybalova、A. Ya. Tikhonov
DOI:10.1007/s11178-005-0361-1
日期:2005.10
Reactions of 2-alkoxypropenals with α-hydroxyamino oximes in neutral medium involve the aldehyde group of the former to afford both acyclic and cyclic azomethine oxides: N-(2-hydroxyiminoalkyl)-N-(2-alkoxy-2-propenylidene)amine oxides and 1-hydroxy-2,5-dihydroimidazole 3-oxides. The state of tautomeric equilibrium between the cyclic and acyclic products depends on the solvent nature and temperature. The reaction in acidic aqueous medium is accompanied by hydrolysis of the vinyl ether moiety in 2-alkoxy-propenals with formation of 2-oxopropionaldehyde which reacts with α-hydroxyamino oxime at the hydroxy-amino group to give substituted pyrazine 1,4-dioxides. The reaction of 2-alkoxypropenals with 1,2-bis-(hydroxyamino)cyclohexane leads to formation of 2-(1-alkoxyvinyl)-1,3-dihydroxyperhydrobenzimidazoles. The structure of the products was proved by IR, UV, and 1H and 13C NMR spectroscopy and X-ray analysis.
作者:N. A. Keiko、Yu. A. Chuvashev、T. A. Kuznetsova、L. V. Sherstyannikova、M. G. Voronkov
DOI:10.1007/bf02641547
日期:1998.12
The reaction of α-ethoxyacrolein with diethyl malonate in the presence of EtONa, lithium diisopropylamide, or the Na2CO3−benzene−Et3(PhCH2)NCl catalytic system proceeds as the Michael addition. In the presence of an equimolar amount of triethylamine, selective 1,2-addition followed by dehydration of the 1,2-adduct occurs. Owing to the strong +M effect of the EtO group, α-ethoxyacrolein is a substantially
Reactions of alcohols with α-alkoxyacroleins at room temperature
作者:N. A. Keiko、Yu. A. Chuvashev、L. G. Stepanova、M. G. Voronkov
DOI:10.1007/bf02641546
日期:1998.12
medium at 20°C under kinetically controlled conditions is the Markovnikoff addition at the C=C bond to form 2,2-dialkoxypropanals (methylglyoxal ketals). Under conditions of thermodynamic control, subsequent acetalization of the aldehyde group occurs to form 1,1,2,2-tetraalkoxypropanes. When the duration of the reaction is further increased in the absence of a water acceptor, the ketal group undegroes hydrolysis
One-pot, three-component cascade synthesis of new tetrasubstituted pyrroles by coupling reaction of 2-functionally substituted 2-alkenals, amines, and nitroethane
作者:Natalia A. Keiko、Nadezhda V. Vchislo、Ekaterina A. Verochkina、Ludmila I. Larina
DOI:10.1016/j.tet.2014.08.040
日期:2014.11
3-aryl(hetaryl)propenals in a one-pot, three-component reaction with primaryamines and nitroethane has been studied. A method for the synthesis of highly functionalized pyrroles (in 36–80% yield) from 2-alkylthiopropenals has been developed on the basis of this reaction. It is found that the reaction proceeds via formation of the intermediateimine of the starting enal, which undergoes 1,2-addition by nitroethane
2-Alkoxy- and 2-alkylthio-2-alkenals in the reactions of electrophilic and nucleophilic addition. DFT study and NBO analysis
作者:Natalia A. Keiko、Tamara N. Aksamentova、Nina N. Chipanina、Ekaterina A. Verochkina、Nadezhda V. Vchislo
DOI:10.1016/j.tet.2012.12.055
日期:2013.2
of theory, and natural bond orbital (NBO) analysis were used to investigate the electron distribution in 3-aryl(hetaryl)substituted2-methoxy- and 2-methylthiopropenals to predict the possibility of electrophilic (Markovnikov-type) or nucleophilic (Michael-type) addition reactions depending on the nature of substituents. The dependence of the CC bond length on the population ratio of its orbitals, P(πC2C3∗)/P(πC2C3)
在理论水平的B3LYP / 6-311 + G **和M06 / 6-311 + G ***的DFT方法和自然键轨道(NBO)分析用于研究3-芳基(杂芳基)取代基中的电子分布根据取代基的性质,使用2-甲氧基和2-甲硫基丙烯醛来预测亲电(马尔可夫尼可夫型)或亲核(迈克尔型)加成反应的可能性。C C键长度对其轨道的填充比P的依赖性(πC2个C3∗)/ P(π C2 C3),用于评价这些取代基的供体和受体的效果。前沿轨道能量值的变化表明,所研究分子的亲电子和亲核能力均取决于其结构。双键C的作用下(作为形成在其原子的天然电荷的差来计算)的偏振方向的变化β-取代基允许人们预测2-烷氧基-和2-烷硫基丙炔的一些代表的极性加成反应的方向。在酸性介质中,Markovnikov和Michael加成的3-芳基(呋喃基)取代的2-甲氧基丙烯的水合活化能略有不同,表明这些过程的可能性相同。